1. Field of the Invention
This invention relates to a body cavity-observing apparatus for observing an internal organ or the like in the body cavity, including an endoscope with an imaging optical system at the forefront thereof to photograph an endoscope image.
2. Description of the Prior Art
Generally, endoscopes to be used in body cavities are classified as rigid endoscopes or fiberscopes. In order to obtain a different endoscope image by moving an endoscope, the rigid endoscope itself must be moved or the fiberscope itself must be moved or bent.
Recently, various endoscope manupulators in which endoscopes are installed have been developed. The endoscope manupulator can rapidly move the endoscope installed therein and obtain a different scope effectively. However, since the endoscope manupulator drives the conventional endoscope only actively, it may degrade the working property because of the movement or bending of the endoscope by an operator. Moreover, if the endoscope manupulator is operated mistakenly from a mistaken data input, the forefront of the endoscope may be made to approach an internal organ more than necessary.
In order to iron out the above conventional matters, the publications of unexamined patent applications Tokukai Hei 8-164148 (JP A 8-164148) and Tokukai Hei 10-290777 (JP A 10-290777) disclose scope-moving techniques. In the former publication, an endoscope follows a medical tool to obtain various endoscope image data on a wide-angle optical image, which are recorded in a memory. Then, the desired image data is selected from the recorded endoscope image data to control the scope of the endoscope. In the latter publication, all or a part of a super wide-angle optical image is displayed from a super wide-angle lens provided at the forefront of an endoscope to control the scope of the endoscope.
In the former case, since the recorded endoscope image data are based on the wide-angle optical image, each image data becomes very small, resulting in the degradation of the resolution and thus, the degradation of the endoscope image quality. In the latter case, if the part of the super wide-angle optical image is selected, the selected optical image also becomes very small, resulting in the degradation of the resolution and thus, the degradation of the endoscope image quality, as mentioned above. Moreover, since the super wide-angle optical lens provides more distorted images at the fringes than at the center, all of the wide-angle optical images cannot be practically provided.
It is an object of the present invention to provide a body cavity-observing apparatus which can provide various endoscope images of good quality without the movement or bending of an endoscope.
Therefore, this invention relates to a body cavity-observing apparatus comprising an endoscope with an imaging optical system on the front edge thereof, a prism movably mounted on the forefront of the imaging optical system, and an actuator to drive the prism on a given command signal, whereby a different endoscope image is obtained through the movement of the prism.
According to the body cavity-observing apparatus of the present invention, different endoscope images can be easily obtained by moving the prism without mechanical movement or mechanical bending of the endoscope itself. As a result, a wide range endoscope images can be easily obtained. Moreover, since only a given area directed by the prism is observed, the resolution of the thus obtained endoscope image can be enhanced. Furthermore, for example under a surgical operation, the working property and the safety of not approaching an internal organ more than necessary are improved.
In a preferred embodiment of the present invention, the prism includes first and second wedge prisms having the same vertical angle that are provided closely. The adjacent opposite surfaces are orthogonal to the optical axis of the wedge prisms. The actuator includes first and second outer tubes which are independently and movably attached to the first and the second wedge prisms, and first and second motors to rotate the first and the second wedge prisms around the optical axis, respectively. In this case, different endoscope images can be easily obtained through the independent rotations of the wedge prisms, and thus, a wide range endoscope image can be easily obtained.
In another preferred embodiment of the present invention, the prism includes one wedge prism. The actuator includes an outer tube movably provided on the periphery of the endoscope, a joining shaft to join the wedge prism and the outer tube, a first motor to tilt the wedge prism for the optical axis via the joining shaft and a second motor to rotate the wedge prism around the optical axis through the rotation of the outer tube. In this case, different endoscope images can be easily obtained through the rotation and tilt of the one wedge prism, and thus, a wide range endoscope image can be obtained.
In still another preferred embodiment of the present invention, the prism includes a liquid prism, and the actuator includes first and second link mechanisms which adjust the tilt angles for two directions orthogonal to the optical axis, respectively. The first and the second link mechanisms comprises pairs of link shafts composed of planar portions joined with the periphery of the liquid prism and orthogonal portions orthogonally followed by the planar portions, link members to support the orthogonal portions of the link shafts, and motors to rotate the link members. In this case, different endoscope images can be easily obtained through the backward and forward movement of the liquid prism, and thus, a wide range endoscope image can be easily obtained.
Moreover, it is desired that the link members each have elongated holes, respectively, and the link shafts are moved backward and forward by slipping the orthogonal portions in the elongated holes through the rotation of the link members by the motors.
In a further preferred embodiment of the present invention, a position-detecting means to detect the position of the prism is provided. An endoscope image is calibrated in its color aberration or distortion on the basis of the prism position information from the position-detecting means. Therefore, the resolution of the endoscope image can be more enhanced.